New Aura Microwave Limb Sounder observations of BrO and implications for Br&amp;lt;sub&amp;gt;y&amp;lt;/sub&amp;gt;

Millán, Luis; Livesey, N. J.; Read, W. G.; Froidevaux, L.; Kinnison, Douglas E.; Harwood, R. S.; MacKenzie, Ian A.; Chipperfield, Martyn P.

doi:10.5194/amt-5-1741-2012

Cited by 17 publications

(18 citation statements)

References 41 publications

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“…During summer and winter, this restricts the usable HO 2 standard product data to between roughly 55 • S and 55 • N, where MLS observes both daytime and nighttime data. In addition to the MLS HO 2 product the MLS HO 2 product, this day-minus-night difference approach to ameliorate biases has been used successfully for the BrO and OH MLS products (Livesey et al, 2006b;Pickett et al, 2008;Millán et al, 2012).…”

Section: Mls Ho Observationsmentioning

confidence: 99%

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Stratospheric and mesospheric HO2 observations from the Aura Microwave Limb Sounder

et al. 2015

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Abstract. This study introduces stratospheric and mesospheric hydroperoxyl radical (HO 2 ) estimates from the Aura Microwave Limb Sounder (MLS) using an offline retrieval (i.e. run separately from the standard MLS algorithm). This new data set provides two daily zonal averages, one during daytime from 10 to 0.0032 hPa (using day-minus-night differences between 10 and 1 hPa to ameliorate systematic biases) and one during nighttime from 1 to 0.0032 hPa. The vertical resolution of this new data set varies from about 4 km at 10 hPa to around 14 km at 0.0032 hPa. A description of the methodology and an error analysis are presented. Comparisons against the Whole Atmosphere Community Climate Model (WACCM), the Superconducting SubmillimeterWave Limb-Emission Sounder (SMILES) and the Far Infrared Spectrometer (FIRS-2) measurements, as well as photochemical simulations, demonstrate the robustness of the retrieval and indicate that the retrieval is sensitive enough to detect mesospheric HO 2 layers during both day and night. This new data set is the first long-term HO 2 stratospheric and mesospheric satellite record and it provides needed constraints to help resolve the O 3 deficit problem and the "HO x dilemma".

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Section: Mls Ho Observationsmentioning

confidence: 99%

“…For this study, an HO 2 offline retrieval has been developed similar to that described by Millán et al (2012). In essence, we compute a daily zonal mean of the radiances, for band 28 and 30, from which we retrieve daily HO 2 concentrations.…”

Section: Offline Retrievalmentioning

confidence: 99%

Stratospheric and mesospheric HO2 observations from the Aura Microwave Limb Sounder

et al. 2015

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“…In Fig. 7, we compare the MLS BrO zonal (25 • N to 35 • N) bi-monthly mean (blue line) of day-night retrieved profiles using the new algorithm described in Millán et al (2012). The date range of MLS data is centered on the balloon flight date, 22 September 2011.…”

Section: Comparison With Other Measurementsmentioning

confidence: 99%

“…In the region between 10 hPa to 4.6 hPa, profiles agree to within 3 ppt. Figure 9 shows the Br y profile (black line) inferred from the SLS BrO profile mixing ratio using the UC Irvine photochemical box model compared to Br y inferred from the MLS BrO average for 2005 using SLIMCAT and WACCM photochemical models (Millán et al, 2012). The range of scientifically useful MLS measurements (10 to 4.6 hPa) is indicated by solid circles.…”

Section: Comparison With Other Measurementsmentioning

confidence: 99%

Stratospheric BrO abundance measured by a balloon-borne submillimeterwave radiometer

et al. 2013

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Measurements of mixing ratio profiles of stratospheric bromine monoxide (BrO) were made using observations of BrO rotational line emission at 650.179 GHz by a balloon-borne SIS (superconductor-insulator-superconductor) submillimeterwave heterodyne limb sounder (SLS). The balloon was launched from Ft. Sumner, New Mexico (34° N) on 22 September 2011. Peak mid-day BrO abundance varied from 16 ± 2 ppt at 34 km to 6 ± 4 ppt at 16 km. Corresponding estimates of total inorganic bromine (Br_y), derived from BrO vmr (volume mixing ratio) using a photochemical box model, were 21 ± 3 ppt and 11 ± 5 ppt, respectively. Inferred Br_y abundance exceeds that attributable solely to decomposition of long-lived methyl bromide and other halons, and is consistent with a contribution from bromine-containing very short lived substances, Br_y^VSLS, of 4 ppt to 8 ppt. These results for BrO and Br_y were compared with, and found to be in good agreement with, those of other recent balloon-borne and satellite instruments

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“…In addition to DOAS, microwave radiometry has also been employed to measure BrO (Millán et al, 2012;Stachnik et al, 2013). Chemical ionization mass spectrometry (CIMS) measurements of atmospheric Br y , using I − or SF − 6 , have largely been limited to BrO, although BrCl, HOBr, and Br 2 have also been detected (Le Chen et al, 2016;Neuman et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

BrO and inferred Bry profiles over the western Pacific: relevance of inorganic bromine sources and a Bry minimum in the aged tropical tropopause layer

et al. 2017

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Abstract. We report measurements of bromine monoxide (BrO) and use an observationally constrained chemical box model to infer total gas-phase inorganic bromine (Br y ) over the tropical western Pacific Ocean (tWPO) during the CON-TRAST field campaign (January-February 2014). The observed BrO and inferred Br y profiles peak in the marine boundary layer (MBL), suggesting the need for a bromine source from sea-salt aerosol (SSA), in addition to organic bromine (CBr y ). Both profiles are found to be C-shaped with local maxima in the upper free troposphere (FT). The median tropospheric BrO vertical column density (VCD) was measured as 1.6×10 13 molec cm −2 , compared to model predictions of 0.9 × 10 13 molec cm −2 in GEOS-Chem (CBr y but no SSA source), 0.4 × 10 13 molec cm −2 in CAM-Chem (CBr y and SSA), and 2.1×10 13 molec cm −2 in GEOS-Chem (CBr y and SSA). Neither global model fully captures the Cshape of the Br y profile. A local Br y maximum of 3.6 ppt (2.9-4.4 ppt; 95 % confidence interval, CI) is inferred between 9.5 and 13.5 km in air masses influenced by recent convective outflow. Unlike BrO, which increases from the convective tropical tropopause layer (TTL) to the aged TTL, gas-phase Br y decreases from the convective TTL to the aged TTL. Analysis of gas-phase Br y against multiple tracers (CFC-11, H 2 O / O 3 ratio, and potential temperature) reveals a Br y minimum of 2.7 ppt (2.3-3.1 ppt; 95 % CI) in the aged TTL, which agrees closely with a stratospheric injection of 2.6 ± 0.6 ppt of inorganic Br y (estimated from CFC-11 correlations), and is remarkably insensitive to assumptions about heterogeneous chemistry. Br y increases to 6.3 ppt (5.6-7.0 ppt; 95 % CI) in the stratospheric "middleworld" and 6.9 ppt (6.5-7.3 ppt; 95 % CI) in the stratospheric "overworld". The local Br y minimum in the aged TTL is qualitatively (but not quantitatively) captured by CAM-Chem, and suggests a more complex partitioning of gas-phase and aerosol Br y species than previously recognized. Our data provide corroborating evidence that inorganic bromine sources (e.g., SSA-derived gas-phase Br y ) are needed to explain the gas-phase Br y budget in the upper free troposphere and TTL. They are also consistent with observations of significant bromide in Upper Troposphere-Lower Stratosphere aerosols. The total Br y budget in the TTL is currently not closed, because of the lack of concurrent quantitative measurements of gas-phase Br y species (i.e., BrO, HOBr, HBr, etc.) and aerosol bromide. Such simultaneous measurements are needed to (1) quantify SSA-derived Br y in the upper FT, (2) test Br y partitioning, and possibly explain the gas-phase Br y minimum in the aged TTL, (3) constrain heterogeneous reaction rates of bromine, and (4) account for all of the sources of Br y to the lower stratosphere.

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New Aura Microwave Limb Sounder observations of BrO and implications for Br<sub>y</sub>

Cited by 17 publications

References 41 publications

Stratospheric and mesospheric HO<sub>2</sub> observations from the Aura Microwave Limb Sounder

Stratospheric and mesospheric HO<sub>2</sub> observations from the Aura Microwave Limb Sounder

Stratospheric BrO abundance measured by a balloon-borne submillimeterwave radiometer

BrO and inferred Br<sub><i>y</i></sub> profiles over the western Pacific: relevance of inorganic bromine sources and a Br<sub><i>y</i></sub> minimum in the aged tropical tropopause layer

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New Aura Microwave Limb Sounder observations of BrO and implications for Br&lt;sub&gt;y&lt;/sub&gt;

Cited by 17 publications

References 41 publications

Stratospheric and mesospheric HO&lt;sub&gt;2&lt;/sub&gt; observations from the Aura Microwave Limb Sounder

Stratospheric and mesospheric HO&lt;sub&gt;2&lt;/sub&gt; observations from the Aura Microwave Limb Sounder

Stratospheric BrO abundance measured by a balloon-borne submillimeterwave radiometer

BrO and inferred Br&lt;sub&gt;&lt;i&gt;y&lt;/i&gt;&lt;/sub&gt; profiles over the western Pacific: relevance of inorganic bromine sources and a Br&lt;sub&gt;&lt;i&gt;y&lt;/i&gt;&lt;/sub&gt; minimum in the aged tropical tropopause layer

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New Aura Microwave Limb Sounder observations of BrO and implications for Br<sub>y</sub>

Stratospheric and mesospheric HO<sub>2</sub> observations from the Aura Microwave Limb Sounder

Stratospheric and mesospheric HO<sub>2</sub> observations from the Aura Microwave Limb Sounder

BrO and inferred Br<sub><i>y</i></sub> profiles over the western Pacific: relevance of inorganic bromine sources and a Br<sub><i>y</i></sub> minimum in the aged tropical tropopause layer